Yes, it is against Facebook's Terms Of Service to have more than one log in to Facebook.
So, if you have two personal profiles or a personal profile and a business page with separate log ins, you do risk getting into trouble with Facebook.
Unfortunately, it is not possible to merge two personal profiles together. You will need to decide which one you want to keep and delete the other one.
Make sure that whichever one you do decide to keep, you make this one the Admin for any Business Pages that you currently manage!
Go into all your Business Pages and ensure that personal profile is the one listed as the Admin or you will lose your access to these pages. In any event, it is always a good idea to ask someone else to also be an Admin - just in case.
When you've chosen which one is to go, you need to decide whether you want to retain any of the information that it currently contains. You can download the following info if you go to Account Settings - via the cog dropdown to the top right of your blue navigation bar. Click General in the left-hand column and then "Download a copy of your Facebook data". Next, click Start My Archive.
You'll get this lot - and, no, you cannot pick and choose what you do and don't want.
Your timeline information (ex: your contact information, interests, groups)
Content that you and your friends have posted to your timeline
Photos and videos that you have uploaded to your account
Your friend list
Notes you have created
Events to which you have RSVP’d
Your sent and received messages
Any comments that you and your friends have made on your timeline posts, photos, and other timeline content
You should be aware that they may not have ALL the info you have previously uploaded.
There is also an enhanced archive containing even more info.
You then have the option to deactivate or delete your account. Deactivate means that you can reactivate it again if you change your mind. Deleting means that it is gone forever, which is probably the option if you have two of them.